I have had breakfast in Bromley-by-Bow.
Where did your bus cross the river? On the Woolwich ferry? Unless it was a single-decker bus, or there is also a Bromley-by Bow SOTR? After all, both East and South have places called Plaistow near places called Bromley. Funny, that.
God bless the internet
http://www.londonbuses.co.uk/routes/108b.html
Though he seems to have omitted your version of the route from his history. Perhaps you could put him straight so that he can update his records.
Here's the route map for the 192, but look at the top left corner, by the arrow pointing towards the Blackwall Tunnel, it says 108B!
http://www.londonbuses.co.uk/maps/_1964-maps/192-64.jpg
The 108b stopping at Here be Dragons, More Dragons, ****ed if I know and Your Guess is as Good as Mine It's South London After All.